Process of manufacturing amorphous carbon



Patented Mar. 17, 1931 PATENT OFFICE ALEXANDER I. ULLRICH, OI CHICAGO,ILLINOIS PROCESS OF MANUFAGTURIN G AMORPHOUS CARBON No Drawing.

My invention in general relates to a process of manufacturing amorphouscarbon, and more particularly to a process of manufacturing lamp blackfrom tar. Still more a specifically, the invention has reference to themanufacture of lamp black from high carbon tar or tar havingconstituents belonging to the class of aromatic hydrocarbons, such ascoal tar and water gas tar.

Now, it is Well known to those familiar with the present art, that lampblack, which is a deep black pigment consisting of carbon in a very finestate of division, is obtained commercially by the imperfect combustion1 of highly carbonaceous substances such as from scraps of rosin andpitch, inferior oils, 1

fats and other similar combustible matter rich in carbon. The finestlamp black, however, is procured by the combustion of oil,

1 obtained in coal tar distillation.

The principal aim or proposal of the res.

ent invention, is to manufacture amorp ous carbon, such as lamp black,directly from coal tar, in a much more economical manner 5 than any ofthe heretofore methods of manufacturing lamp black.

I am aware that lamp black has also heretofore been manufactured byburning tar in ovens connected with brick chambers in P "17 which largequantities of soot formed in this process, deposit before the gasesescape through the chimney. This method of manufacture is far moreexpensive than my improved method, to be hereinafter described.

1& Then, too, this manner of procuring lamp black by the incompletecombustion of carbonaceous matter results in noxious gases being evolvedwhich usually are permltted to escape into the atmosphere therebyfouling the air of the community. My proposed improved method ofmanufacturing lamp black does not require the combustion of anycarbonaceous matter, and hence, no noxious gases are generated. Also,more carbon of J the above character can be obtained by my improvedrocess from a predetermined quantity 0 tar than any other method orprocess that I am aware of. r

The primary object therefore of the pres; ent invention, is to providean improved Application filed April 24, 1925. Serial No. 25,619.

method of manufacturing amorphous carbon, such as lamp black, from highcarbon tars.

Other objects and advantages of the present invention will more fullyappear from "T3 the following description of the method.

The first step involved, is to bring the tar to a liquid form. Aspreviously mentioned, the tar is one having a relatively great amount ofcarbon therein. I prefer to use a coal tar ora water gas tar.Liquefaction of the tar is carried out The tar may be placed inreceptacle and heated in any desirable or by heating the tar. anysuitable Lil convenient manner.

I find it desirable to add a solvent to the liquid tar. The solventemployed may be benzol, amyl acetate, or any solvent of a likeorsuitablecharacter. In carrying out my process benzol was used as thesolvent, due to its being a very cheap and easy one to procure.

The solvent, when added at this stzmc of the process, seems to aid inthe liquetying of the coal tar. The solvent added may be, equal involume to the coal tar being heated. That is to say, if one gallon oftar is heated, a gallon of solvent is added thereto. This solvent freesthecarbon oftho tar from the soluble constituents thereof, the carbonparticles being then held in suspension in the resulting solution. I

The nextstep in the process consists in adding to the mass of the liquidtar an oil of comparatively high hydrocarbon content. a"; The oils Ihave used have a relatively high viscosity and are much more greasy incharacter than the light oils used as a solvent.

I have employed common fuel oil, gasoline, turpentine, kerosene, andmany other such 7' fluids, all of which have proven satisfaotory. Commonfuel oil and kerosene being the cheapest ofthose available on themarket, are obviously preferable.

This oil when added to the heated liquid T-l causes, it to curdle. This'curdling of the liquid is a combinedchemical and physical action whichcauses coagulation of the liquid and rapid precipitation of the carbonparticles together with a small proportion I of impurities, such as theless readily soluble resins and gums. The resultant coagulum sinks tothe bottom of the container Whereas the oil and solvent rise to the top.The amount of oil added to the fluid should be sufficient to obtain themaximum amount of coagulated'matter from the liquid. That is to say, oilshould be added to the liquid until no more coagulation takes place.

The next step in the process consistsin pouring off the oily fluid fromthe top of the residue in the bottom of the container The remainingresidue or coagulum is of a brownish tint and is the matter from which Iprocure carbon.

Now, the next step in the process consists in removing the brown colorfrom the residue. vIn other Words, it is necessary, in order to obtainrelatively pure carbon or lamp black that the aforementioned residue bethoroughly washed. 'I find that this brown color and other impuritiesmay be Washed from the residue by adding solvent thereto. The solventused for this purpose is a product obtained in the manufacture of Watergas; This product is obtained by scrubbing the Water gas and containstoluol, benzol, and other solvents, being known commercially as lightoil. From time to 1 time a sample ofthe matter may be removed from theliquid and tested to determine it all of the brown matter has beenremoved therefrom. The test I employed Was the usual test for carbon,namely, the White lead test. That is to say, When all of the brownmatter has been removed from the residue, the test Will give a graycolor. I

solvent such as light oil and thereby removing the soluble constituentstherefrom so as to produce a residuum of substantially pure carbon, andthenseparating the solvent from the residuum of carbon and drying thelatter.

In Witness whereof, I hereunto subscribe my name this 18th :day ofApril,,1925

ALEXANDER L. ULLRICH.

desire it understood also that the solvent employed for purifying thecoagulum, may

be of any suitable type or kind, though I preferably use light-oil aspreviously mentioned.

The last step in the process consists in pouring ofi the. solvent anddrying the carbon or lamp black. Any suitable drying apparatus may beemployed. 7

By employing the above method in 1nanufacturing lamp black from coal taror Water gas tar, I find that about two-thirds of the tar used may beconverted into lamp black. In other Words, for every pound of tar, Iamable to obtain two-thirds of a pound of lamp black. This by farexceeds the amount obtainedfrom tar "heretofore.

Obviously the solvents employed may be recovered by any suitabledistilling process and used over again.

It should beunderstood, however, that my invention is not to be limitedto the exact procedure above described, but only o th app/ id d c i Iaim= p ocess of nrediiping eer bon ital-'11 tar which consists Ilsofaras definedby the scope andspirit in liquefying the tar by

